The invention relates to limitation of terminal equipment use of home subscribers of a network in a telecommunications system, and particularly to limitation of the use of mobile stations of a mobile system.
In most data transmission systems supporting subscriber mobility, subscribers and terminal equipments are not fixedly assigned to each other; instead, subscriber-specific subscriber identity modules and individual equipment identities for differentiating between terminal equipments are used. Examples for a data transmission system like this are the digital Pan-European cellular radio system GSM (Global System for Mobile Communications), and derivatives of the GSM.
An identity module used for identifying the subscriber, e.g. a SIM card (Subscriber Identity Module) used in the GSM, is a processor card or smart card positioned in a terminal equipment. The card enables the subscriber to use the card-controlled terminal equipment, and it contains e.g. information helping to identify the subscriber, e.g. a number identifying a mobile station subscriber. An example for an identity like this is an IMSI (International Mobile Subscriber Identity) used in the GSM, the IMSI comprising a land code for mobile communication, a mobile network identity, and a mobile subscriber identity.
To identify a terminal equipment, an identity identifying the terminal equipment stored in the terminal during the manufacture is transmitted to the network. An example for an identity like this is an IMEI (International Mobile Equipment Identity) used in the GSM, the IMEI comprising a type approval code, a manufacturer""s code, and a serial number.
Mobile networks comprise a facility in which an equipment identity of a terminal equipment used by a subscriber, i.e. an IMEI in the GSM, is checked by inquiring the equipment identity of the subscriber. The equipment identity of the subscriber is checked, for example, to make sure that the terminal equipment concerned is not a stolen one or that the use of the equipment will not cause interference in the network. The equipment identity can be inquired of the subscriber e.g. always when the terminal equipment has established a connection with a mobile exchange, or in connection with location updating. The equipment identity of the subscriber is compared with information on equipment identities located in an Equipment Identity Register EIR or elsewhere in the mobile system, and as a result of the comparison, the use of the terminal equipment is either forbidden or allowed. The equipment identity register EIR of the GSM, for example, comprises lists of terminal equipment identities or series of such identities: a xe2x80x98white listxe2x80x99 of all the equipments allowed in the system, a xe2x80x98black listxe2x80x99 of all the equipments forbidden in the system, and a xe2x80x98grey listxe2x80x99 of all the equipments under supervision in the system. The maintenance of the lists in the system is centralised, and the operators can either use the lists directly or copy them in their own registers. The operators first check the black, then the grey and finally the white list.
In the above prior art mobile system in which a subscriber can make and receive phone calls at any terminal equipment of the system whatsoever, a problem arises when the operator wants to ensure that some or all of the home subscribers of the network use only terminal equipments sold or otherwise approved of by the operator in communication within the network of the operator.
The object of the invention is to solve the above problem and to provide a method by which the operator, if it so desires, can supervise the terminal equipments used by the home subscribers in the network of the operator. The object is achieved by a method according to the invention, which is characterized by maintaining a home equipment list of terminal equipments allowed to the home subscribers of the network; receiving from the terminal equipment a subscriber identity of the user; receiving from the terminal equipment an equipment identity; checking on the basis of the subscriber identity whether the subscriber is a home subscriber of the network, and if so, checking the home equipment list of the network to see whether the terminal equipment is an allowed one, and if the terminal equipment is not an allowed equipment, limiting the use of the equipment.
The invention also relates to an equipment register in which the method of the invention can be applied. An equipment register is part of a telecommunications system that comprises at least one network. The equipment register comprises reception means for receiving a terminal equipment check request form network infrastructure; comparison means for making a terminal equipment check: and response means for responding to the terminal equipment check request. The equipment register according to the invention is characterized in that it comprises, for at least one network, a home equipment list that contains information on the terminal equipments allowed to the home subscribers of the network; that in response to a terminal equipment check request concerning a home subscriber of the network, the comparison means are arranged to check the home equipment list of the network to see whether the terminal equipment is an allowed one; and that the response means are arranged to transmit a response to the network infrastructure, the response indicating the result of the check at least when the terminal equipment is riot on the home equipment list.
The invention also relates to a mobile system in which the method of the invention can be used. The mobile system comprises terminal equipments with individual equipment identities, subscribers with individual subscriber identities, and several networks each of which comprises at least one controller and means for receiving from a terminal equipment the equipment identity and the subscriber identity of the user. The mobile system according to the invention is characterized by comprising memory means that comprise, for at least one network, a home equipment list defining a group of equipment identities allowed to the home subscribers of the network, comparison means for comparing an equipment identity received from a home subscriber of the network with the equipment identities on the home equipment list in the memory means, and indication means for indicating an equipment identity lacking from the home equipment list.
The expression xe2x80x98several networksxe2x80x99 here means at least two different networks.
The invention improves the possibilities of a mobile system operator to supervise whether or not the home subscribers use terminal equipments approved of by the operator, and to treat them accordingly. If a terminal equipment is one that has not been approved of by the operator for the home subscribers, then the use of the terminal equipment can be prevented with the exception of emergency calls, or incoming calls may be allowed but outgoing calls forbidden or charged for extra. The invention thus gives the operator greater freedom to price both calls and terminal equipments: for example, a smaller charge for a call can be compensated for with more expensive terminal equipments.
Another advantage of the invention is that any changes needed for implementing the invention can be limited to a clearly defined area, mainly to software that controls a visitor location register and an equipment register. The implementation of the invention does not in any way disturb the operation of network elements to which the operation provided by the invention has not been added.
In addition, in a preferred embodiment of the invention in which equipment identities are connected with a subscriber identity, the operator has still greater freedom to set prices, since each subscriber can receive even more individual treatment. To some subscriber, even all terminal equipments allowed in the system can be allowed.
Preferred embodiments of a method, an equipment register and a mobile system according to the invention appear from attached dependent claims 2, 3, 5, 7 to 9.